**9. Barbados nut (***Jatropha curcas***) as a biofuel**

### **9.1 Global production of Jatropha**

Jatropha is a shrub, belonging to the Euphorbiaceae family, thriving in various environments and across a wide range of ecosystems. It is a plant that can survive several months with minimal water and can actually live up to 40 years or more. It is not edible to human beings or animals. The jatropha industry is in its very early stages, covering a global area estimated at some 900,000 ha. More than 85 percent of jatropha plantings are in Asia, chiefly Myanmar, India, China and Indonesia. Africa accounts for around 12 percent or

Potentials of Selected Tropical Crops and Manure as Sources of Biofuels 19

and carbonate contents than that of control digesters. This co-digestion resulted in 92.94%

Dhanya et al., (2009) researched the biogas production potential of Jatropha (*Jatropha curcas*, L) Fruit Coat (JFC) alone and in combination with cattle dung (CD) in various proportions at 15 per cent total solids by batch phase anaerobic digestion for a period of ten weeks HRT (Hydraulic Retention Time) under a temperature of 350C+10C. The maximum biogas production was noticed in cattle dung and Jatropha Fruit Coat in 2:1 ratio with 403.84 L/kg dry matter followed by 3:1,1:2, 1:1 and 1:3 having 329.66, 219.77, 217.79, 203.64 L/kg dry matter respectively as compared to 178.49 L/kg dry matter in CD alone. The JFC alone was found to produce 91% of total biogas of that obtained from cattle dung. The per cent methane content of the biogas in all the treatments was found on par with cattle dung.

Ways and means have been sought for many years to be able to produce oil-substitute fuel. Biodiesel extracted from fresh or used vegetable oil whether edible or not, is one such renewable alternative under consideration. Merits of biodiesel are that it can be directly used in engines with little or no modifications; contains little or no sulphur; no aromatics; has a higher cetane number and contains about 10% built-in oxygen and these properties help it burn fully with the result of having less carbon monoxide production, less unburnt carbon and less particulate matter residues. The production of biodiesel would be cheap as it could preferably be extracted from non edible oil sources. *Jatropha curcas* (Linaeus), a nonedible oil-bearing and drought-hardy shrub with ecological advantages, belonging to the *Euphorbiaceae* family, has been found to be the most appropriate renewable alternative source of biodiesel. Presently, the procedure for biodiesel production from jatropha seeds starts with harvesting whole ripe fruits. These fruits are then opened to remove the typically 3 or 4 seeds contained in each fruit. (A matured plant produces about 20kg of seeds in a year). These seeds are then sundried and afterwards stones, sticks, mouldy or damaged seeds and other foreign materials are handpicked from the batch of dried seeds. Next, this cleaned batch of seeds is crushed in an oil extraction machine to free the oil. This extracted oil is then filtered to remove impediments and the oil is poured in air-tight containers for storage. The extracted and filtered vegetable oil can be used directly as a fuel in suitable diesel engines without undergoing the trans-esterification process (Achten et al., 2008). However, to make it more useful in many engines, this Jatropha oil has to undergo a transesterification process of the triglyceride molecules in fats and oils with light weight alcohols like ethanol and methanol in a reactor in order to convert it to biodiesel. After being put into the reactor, the Jatropha oil settles; it is washed and purified by evaporation, and the liquid produced is biodiesel. Under optimal conditions, *Jatropha curcas* produces a higher oil yield per hectare compared to peanuts (*Arachis hypogea*), sunflower (*Helianthus annus*), soyabean (*Glycine max*), maize (*Zea mays*) and cotton (*Gossypium* species) (Kaushik et al., 2007). Biodiesel is a promising alternative because it is a renewable liquid fuel source that can be

used alone and alternatively blended with petroleum-based diesel.

Jatropha's potential as a new energy source comes at time when interest in biofuel production is at an all-time high. As observed by Parwira (2010), biofuel production could potentially position developing nations to become net exporters of fuel which could greatly advance their objectives of economic independence. The paper noted further that many

decrease in chemical oxygen demand.

**9.3 Biodiesel production from Jatropha** 

approximately 120,000 ha, mostly in Madagascar and Zambia, but also in Tanzania and Mozambique. The West African nations of Mali, Ghana and Senegal have also established lofty production targets for Jatropha notably; to cultivate 320,000 ha of *Jatropha curcas* in Senegal by 2012 and 1 million ha in Ghana in the medium term (OECD, 2008). Latin America has approximately 20,000 ha of jatropha, mostly in Brazil. The area planted with jatropha was projected to grow to 4.72 million ha by 2010 and 12.8 million ha by 2015. By then, Indonesia is expected to be the largest producer in Asia with 5.2 million ha, Ghana and Madagascar together will have the largest area in Africa with 1.1 million ha, and Brazil is projected to be the largest producer in Latin America with 1.3 million ha. Total biogas generation potential from *Jatropha curcas* cakes in India has been estimated as 2,550 million m3 from 10.2 lakh metric ton of *J. curcas* oil seed cakes.

*Jatropha curcas* contains about 30% oil leaving behind presscake (75% including about 5% losses of oil in extraction process in the mechanical expeller) with residual oil. The oil is used for preparing bio-diesel (Achten et al., 2008) and in soap preparation. The press cake is rich in organic matter (Abreu, 2009). It can be used as manure, as feedstock for biogas production, animal feed and so forth. (Agarwal, 2007). Also, *Jatropha* oil cake is used for enriching the soil (Reyadh, 1997). Envis (2004) observed that *Jatropha* oil cake is an organic fertilizer that is superior to cattle manure and it is in great demand by farmers.

#### **9.2 Biogas production from Jatropha**

Ali et al., (2010), studied the use of *Jatropha curcas* defatted waste as an alternative feed in biogas plant for its bio-methanisation. The paper observed that as it remains as defatted cake after the extraction of non-edible oil from *Jatropha* seeds, it cannot be used directly for any purpose due to presence of toxic substance called 'curcin'. This toxin renders it unsafe for the animal feed and other purposes. It contains 5.73% nitrogen, 1.5% phosphorus and about 1% potassium. On the basis of its chemical composition, its application as substrate to the biogas plant can be a sustainable alternative as compared to the other applications of *Jatropha* press cake. The study was conducted on a floating drum type biogas plant. The study observed that the biogas plant, initially charged with pure cattle dung, when gradually replaced with *Jatropha* oil cake (0 - 100%), increased the biogas production up to approximately 25% in reasonable time duration. A significant increase in the percentage of nitrogen, phosphorus and potassium during the biofermentation process invokes the use of the effluent slurry as organic manure. Simultaneous reduction in the amount of the oil (5.67 to 3.95%) sustains the possibility of degradation of oil during methanisation. The plant has showed higher biogas yields at low temperatures also. Therefore, *Jatropha* defatted waste can successfully be used as an addition as well as substrate in already running cattle dung based biogas plant to get higher yield of biogas in comparison to cattle dung feed.

A laboratory experiment was conducted to find out the biogas production potential of dried, powdered Jatropha cake mixed with buffalo dung at 6% total solids (Prateek, 2009). The experiment was run on daily feeding basis in 5-litre capacity glass digesters for 180 days, while biogas production was recorded at 24 hr interval. Quality of biogas and nutritive value of effluent slurry was also determined. Results show significantly higher (139.20%) biogas production in test (Jatropha cake + Buffalo dung) over control (Buffalo dung only) digesters with methane content of 71.74%. Nutritive value of effluent slurry of test digester was significantly higher in terms of available nitrogen and potassium; calcium; magnesium and carbonate contents than that of control digesters. This co-digestion resulted in 92.94% decrease in chemical oxygen demand.

Dhanya et al., (2009) researched the biogas production potential of Jatropha (*Jatropha curcas*, L) Fruit Coat (JFC) alone and in combination with cattle dung (CD) in various proportions at 15 per cent total solids by batch phase anaerobic digestion for a period of ten weeks HRT (Hydraulic Retention Time) under a temperature of 350C+10C. The maximum biogas production was noticed in cattle dung and Jatropha Fruit Coat in 2:1 ratio with 403.84 L/kg dry matter followed by 3:1,1:2, 1:1 and 1:3 having 329.66, 219.77, 217.79, 203.64 L/kg dry matter respectively as compared to 178.49 L/kg dry matter in CD alone. The JFC alone was found to produce 91% of total biogas of that obtained from cattle dung. The per cent methane content of the biogas in all the treatments was found on par with cattle dung.

### **9.3 Biodiesel production from Jatropha**

18 Biogas

approximately 120,000 ha, mostly in Madagascar and Zambia, but also in Tanzania and Mozambique. The West African nations of Mali, Ghana and Senegal have also established lofty production targets for Jatropha notably; to cultivate 320,000 ha of *Jatropha curcas* in Senegal by 2012 and 1 million ha in Ghana in the medium term (OECD, 2008). Latin America has approximately 20,000 ha of jatropha, mostly in Brazil. The area planted with jatropha was projected to grow to 4.72 million ha by 2010 and 12.8 million ha by 2015. By then, Indonesia is expected to be the largest producer in Asia with 5.2 million ha, Ghana and Madagascar together will have the largest area in Africa with 1.1 million ha, and Brazil is projected to be the largest producer in Latin America with 1.3 million ha. Total biogas generation potential from *Jatropha curcas* cakes in India has been estimated as 2,550 million

*Jatropha curcas* contains about 30% oil leaving behind presscake (75% including about 5% losses of oil in extraction process in the mechanical expeller) with residual oil. The oil is used for preparing bio-diesel (Achten et al., 2008) and in soap preparation. The press cake is rich in organic matter (Abreu, 2009). It can be used as manure, as feedstock for biogas production, animal feed and so forth. (Agarwal, 2007). Also, *Jatropha* oil cake is used for enriching the soil (Reyadh, 1997). Envis (2004) observed that *Jatropha* oil cake is an organic

Ali et al., (2010), studied the use of *Jatropha curcas* defatted waste as an alternative feed in biogas plant for its bio-methanisation. The paper observed that as it remains as defatted cake after the extraction of non-edible oil from *Jatropha* seeds, it cannot be used directly for any purpose due to presence of toxic substance called 'curcin'. This toxin renders it unsafe for the animal feed and other purposes. It contains 5.73% nitrogen, 1.5% phosphorus and about 1% potassium. On the basis of its chemical composition, its application as substrate to the biogas plant can be a sustainable alternative as compared to the other applications of *Jatropha* press cake. The study was conducted on a floating drum type biogas plant. The study observed that the biogas plant, initially charged with pure cattle dung, when gradually replaced with *Jatropha* oil cake (0 - 100%), increased the biogas production up to approximately 25% in reasonable time duration. A significant increase in the percentage of nitrogen, phosphorus and potassium during the biofermentation process invokes the use of the effluent slurry as organic manure. Simultaneous reduction in the amount of the oil (5.67 to 3.95%) sustains the possibility of degradation of oil during methanisation. The plant has showed higher biogas yields at low temperatures also. Therefore, *Jatropha* defatted waste can successfully be used as an addition as well as substrate in already running cattle dung

fertilizer that is superior to cattle manure and it is in great demand by farmers.

based biogas plant to get higher yield of biogas in comparison to cattle dung feed.

A laboratory experiment was conducted to find out the biogas production potential of dried, powdered Jatropha cake mixed with buffalo dung at 6% total solids (Prateek, 2009). The experiment was run on daily feeding basis in 5-litre capacity glass digesters for 180 days, while biogas production was recorded at 24 hr interval. Quality of biogas and nutritive value of effluent slurry was also determined. Results show significantly higher (139.20%) biogas production in test (Jatropha cake + Buffalo dung) over control (Buffalo dung only) digesters with methane content of 71.74%. Nutritive value of effluent slurry of test digester was significantly higher in terms of available nitrogen and potassium; calcium; magnesium

m3 from 10.2 lakh metric ton of *J. curcas* oil seed cakes.

**9.2 Biogas production from Jatropha** 

Ways and means have been sought for many years to be able to produce oil-substitute fuel. Biodiesel extracted from fresh or used vegetable oil whether edible or not, is one such renewable alternative under consideration. Merits of biodiesel are that it can be directly used in engines with little or no modifications; contains little or no sulphur; no aromatics; has a higher cetane number and contains about 10% built-in oxygen and these properties help it burn fully with the result of having less carbon monoxide production, less unburnt carbon and less particulate matter residues. The production of biodiesel would be cheap as it could preferably be extracted from non edible oil sources. *Jatropha curcas* (Linaeus), a nonedible oil-bearing and drought-hardy shrub with ecological advantages, belonging to the *Euphorbiaceae* family, has been found to be the most appropriate renewable alternative source of biodiesel. Presently, the procedure for biodiesel production from jatropha seeds starts with harvesting whole ripe fruits. These fruits are then opened to remove the typically 3 or 4 seeds contained in each fruit. (A matured plant produces about 20kg of seeds in a year). These seeds are then sundried and afterwards stones, sticks, mouldy or damaged seeds and other foreign materials are handpicked from the batch of dried seeds. Next, this cleaned batch of seeds is crushed in an oil extraction machine to free the oil. This extracted oil is then filtered to remove impediments and the oil is poured in air-tight containers for storage. The extracted and filtered vegetable oil can be used directly as a fuel in suitable diesel engines without undergoing the trans-esterification process (Achten et al., 2008). However, to make it more useful in many engines, this Jatropha oil has to undergo a transesterification process of the triglyceride molecules in fats and oils with light weight alcohols like ethanol and methanol in a reactor in order to convert it to biodiesel. After being put into the reactor, the Jatropha oil settles; it is washed and purified by evaporation, and the liquid produced is biodiesel. Under optimal conditions, *Jatropha curcas* produces a higher oil yield per hectare compared to peanuts (*Arachis hypogea*), sunflower (*Helianthus annus*), soyabean (*Glycine max*), maize (*Zea mays*) and cotton (*Gossypium* species) (Kaushik et al., 2007). Biodiesel is a promising alternative because it is a renewable liquid fuel source that can be used alone and alternatively blended with petroleum-based diesel.

Jatropha's potential as a new energy source comes at time when interest in biofuel production is at an all-time high. As observed by Parwira (2010), biofuel production could potentially position developing nations to become net exporters of fuel which could greatly advance their objectives of economic independence. The paper noted further that many

Potentials of Selected Tropical Crops and Manure as Sources of Biofuels 21

experiments. Experimental results revealed that a 12:1 molar ratio of methanol to oil, addition of 1.5% (w/v) CaO catalyst, 70ºC reaction temperature, 2% water content in the oil produced more than 95% biodiesel yield after 3 hours reaction time. Calcium oxide activated with ammonium carbonate was an efficient super base catalyst for a high yield transesterification reaction and the base strength of CaO was more than 26.5 after dipping in ammonium carbonate solution followed by calcinations. Transesterification of Jatropha oil using supercritical methanol was also studied under the range of temperature from 120ºC to 250ºC, and range of pressure from 5 - 37 bars using superbase catalyst CaO and acid catalyst. The reaction products were analyzed for their content of glycerol by high performance liquid chromatography (HPLC) and this revealed that the process of

The typical fuel properties of *Jatropha curcas* L, oil are as shown in Table 4 below. These

1 Calorific value (MJkg-1) 39.77 Kumar and Sharma (2008)

The grass family (gramineae or poaceae) is perhaps the most successful taxonomic group in the plant kingdom. Members of this group number about 9000 species distributed in about 635 genera and they grow in all ecosystems and agroclimatic zones. From economic and ecological standpoints, they are the most important species in the plant kingdom. The pea family (leguminosae or fabaceae) is the largest family of flowering plants and also contains a large number of species found flourishing in many ecosystems and agroclimatic zones. Both families of plants contain domesticated crops and wild plants which are being researched for their potentials as reliable sources of biofuels. These plants certainly have a significant role to play in an anticipated global scenario which is 100% dependent on bioenergy in the

A study by Sidibe and Hashimoto (1990) documented the fact that grass straw can be fermented to methane and the yield can be relatively high. This laboratory experiment showed that the ultimate methane yield of rye grass straw (341+ 5ml/g VS) and fescue grass

41.51 Kywe and Oo (2009)

2 Cetane number 51 Dinh et al., (2009) 3 Cloud point (0C) 2 Achten et al., (2008) 4 Flash point (0C) 235 Achten et al., (2008)

6 Relationship C/H (%wt) 13.11 Abreu (2009) 7 Relative density 0.87 Kywe and Oo (2009) 8 Sulphur content (%wt) 0.04 Abreu (2009) 9 Carbon residue (%) 0.02 Dinh et al., (2009)

supercritical transesterification achieved a yield of more than 95% after 1 hour.

S/N Property Numerical quantity Reference

properties show that jatropha biodiesel is a good quality biofuel.

5 Kinematic viscosity at 400C

Table 4. Fuel Properties of *Jatropha curcas* oil

**10.1 Global availability of grasses and other wild plants** 

**10.2 Biogas production from grasses and wild plants** 

**10. Common grasses as biofuels** 

(mm2sec-1 )

near future.

international corporations in Scandinavia, China, and Europe are purchasing tracts of land in developing countries (especially African countries) in an attempt to capitalize on this growth industry. New uses are being found for biofuel continually and this creates an impetus to strengthen efforts to produce them. In fact, several wireless communication companies have constructed cellular network base stations that are powered by *Jatropha*based biofuel (Katembo and Gray, 2007). Presently, corn ethanol has a yield of 3100–4000 L/ha. This is still much higher than *Jatropha curcas* which is approximately 460-680 L/Ha of oil (Dar 2007). However, the production of Jatropha biodiesel is still very attractive largely due to its excellent fuel properties.

Kywe and Oo (2009) obtained a biodiesel yield of 30 gallons/day from a pilot plant which produced oil from Jatropha. The biodiesel demonstrated excellent fuel properties and it was found to be of very good quality. Tomomatsu and Swallow (2007) studied the economics and potential value of *Jatropha curcas* biodiesel production in Kenya and noted that in recent years, the production of *Jatropha curcas* has been widely promoted by private enterprises, non-governmental organizations and development agencies as one of the most viable candidates for biodiesel feedstock in Africa. While multiple benefits of jatropha production such as a petroleum product substitute, greenhouse gas mitigation and rural development are emphasized, the viability of production at farm level is questioned. The study revealed that the profitability of jatropha production for smallholder farmers is expected to be minimal unless farm-level production is accompanied by significant investments and policies targeted at enhancing production of the crop. However another economic study which took place in Mali showed that when all uses of Jatropha were taken into consideration, a rate of return of 135% could be achieved (Dinh et al., 2009).

Veljkovic et al., (2006) noted that biodiesel, which is made from renewable sources, consists of the simple alkyl esters of fatty acids. As a future prospective fuel, biodiesel has to compete economically with petroleum diesel fuels. The use of the less expensive feedstock containing fatty acids such as inedible oils, animal fats, waste food oil and byproducts of the refining vegetables oils reduces the costs of producing biodiesel. Therefore the availability and sustainability of supplies of less expensive feedstock will be a crucial determinant in competitively delivering biodiesel to commercial fuel filling stations. Such less expensive feedstock can come from inedible vegetable oils, mostly produced by seed-bearing trees and shrubs such as Jatropha curcas, a plant which has no competing food uses and which grows widely in tropical and subtropical climates across the world (Openshaw, 2000). Berchmans and Hirata (2008) developed a technique to produce biodiesel from crude Jatropha curcas seed oil having high free fatty acids (15% FFA). The high FFA level of the oil was reduced to less than 1% by a two-step pretreatment process. The first step was carried out with 0.60 w/w methanol-to-oil ratio in the presence of 1% w/w H2SO4 as an acid catalyst in 1-hr reaction at 500C. After the reaction, the mixture was allowed to settle for 2 hr and the methanol–water mixture which separated at the top layer was removed. The second step involved trans esterification using 0.24 w/w methanol to oil and 1.4% w/w NaOH to oil as alkaline catalyst to produce biodiesel at 650C. The final yield for methyl esters of fatty acids was achieved for 90% in 2 hr.

Hawash et al., (2011) investigated the trans-esterification of *Jatropha curcas* oil (JCO) to biodiesel using CaO as a solid base catalyst by determining the effects of molar ratio of methanol to oil, water content, reaction time and mass ratio of catalyst to oil in laboratory

international corporations in Scandinavia, China, and Europe are purchasing tracts of land in developing countries (especially African countries) in an attempt to capitalize on this growth industry. New uses are being found for biofuel continually and this creates an impetus to strengthen efforts to produce them. In fact, several wireless communication companies have constructed cellular network base stations that are powered by *Jatropha*based biofuel (Katembo and Gray, 2007). Presently, corn ethanol has a yield of 3100–4000 L/ha. This is still much higher than *Jatropha curcas* which is approximately 460-680 L/Ha of oil (Dar 2007). However, the production of Jatropha biodiesel is still very attractive largely

Kywe and Oo (2009) obtained a biodiesel yield of 30 gallons/day from a pilot plant which produced oil from Jatropha. The biodiesel demonstrated excellent fuel properties and it was found to be of very good quality. Tomomatsu and Swallow (2007) studied the economics and potential value of *Jatropha curcas* biodiesel production in Kenya and noted that in recent years, the production of *Jatropha curcas* has been widely promoted by private enterprises, non-governmental organizations and development agencies as one of the most viable candidates for biodiesel feedstock in Africa. While multiple benefits of jatropha production such as a petroleum product substitute, greenhouse gas mitigation and rural development are emphasized, the viability of production at farm level is questioned. The study revealed that the profitability of jatropha production for smallholder farmers is expected to be minimal unless farm-level production is accompanied by significant investments and policies targeted at enhancing production of the crop. However another economic study which took place in Mali showed that when all uses of Jatropha were taken into

Veljkovic et al., (2006) noted that biodiesel, which is made from renewable sources, consists of the simple alkyl esters of fatty acids. As a future prospective fuel, biodiesel has to compete economically with petroleum diesel fuels. The use of the less expensive feedstock containing fatty acids such as inedible oils, animal fats, waste food oil and byproducts of the refining vegetables oils reduces the costs of producing biodiesel. Therefore the availability and sustainability of supplies of less expensive feedstock will be a crucial determinant in competitively delivering biodiesel to commercial fuel filling stations. Such less expensive feedstock can come from inedible vegetable oils, mostly produced by seed-bearing trees and shrubs such as Jatropha curcas, a plant which has no competing food uses and which grows widely in tropical and subtropical climates across the world (Openshaw, 2000). Berchmans and Hirata (2008) developed a technique to produce biodiesel from crude Jatropha curcas seed oil having high free fatty acids (15% FFA). The high FFA level of the oil was reduced to less than 1% by a two-step pretreatment process. The first step was carried out with 0.60 w/w methanol-to-oil ratio in the presence of 1% w/w H2SO4 as an acid catalyst in 1-hr reaction at 500C. After the reaction, the mixture was allowed to settle for 2 hr and the methanol–water mixture which separated at the top layer was removed. The second step involved trans esterification using 0.24 w/w methanol to oil and 1.4% w/w NaOH to oil as alkaline catalyst to produce biodiesel at 650C. The final yield for methyl esters of fatty acids

Hawash et al., (2011) investigated the trans-esterification of *Jatropha curcas* oil (JCO) to biodiesel using CaO as a solid base catalyst by determining the effects of molar ratio of methanol to oil, water content, reaction time and mass ratio of catalyst to oil in laboratory

consideration, a rate of return of 135% could be achieved (Dinh et al., 2009).

due to its excellent fuel properties.

was achieved for 90% in 2 hr.

experiments. Experimental results revealed that a 12:1 molar ratio of methanol to oil, addition of 1.5% (w/v) CaO catalyst, 70ºC reaction temperature, 2% water content in the oil produced more than 95% biodiesel yield after 3 hours reaction time. Calcium oxide activated with ammonium carbonate was an efficient super base catalyst for a high yield transesterification reaction and the base strength of CaO was more than 26.5 after dipping in ammonium carbonate solution followed by calcinations. Transesterification of Jatropha oil using supercritical methanol was also studied under the range of temperature from 120ºC to 250ºC, and range of pressure from 5 - 37 bars using superbase catalyst CaO and acid catalyst. The reaction products were analyzed for their content of glycerol by high performance liquid chromatography (HPLC) and this revealed that the process of supercritical transesterification achieved a yield of more than 95% after 1 hour.


The typical fuel properties of *Jatropha curcas* L, oil are as shown in Table 4 below. These properties show that jatropha biodiesel is a good quality biofuel.

Table 4. Fuel Properties of *Jatropha curcas* oil
